Use of organic sulfonic acids to accelerate the vulcanization of butyl rubber with dimethylol phenols



United States Patent 1 2,794,009 USE OF ORGANIC SULFONIC ACIDS T0 ACCEL- ERATE THE VULCANIZATION OF BUTYL RUB- BER WITH DEVIETHYLOL PHENOLS Paul F. Gunberg, Ridgewood, N. 3., assignor to United States Rubber Company, New York, N. Y., a corporation of New Jersey No Drawing. Application October 12, 1953, Serial No. 385,689 11 Claims. (Cl. 26033.6)

This invention relates to a process for promoting the reactions of Butyl rubber with dimethylol phenols, as well as to the reaction products obtained thereby.

A copending application of Tawney and Little, Serial No. 266,146, filed January 12, 1952, now Patent No. 2,701,895, discloses and claims the vulcanization of Butyl rubber with dimethylol phenols. It has been desired to render the vulcanization of Butyl rubber with dimethylol phenols more convenient and more economical, by reducing the time and temperature necessary to attain a practical cure by this method. Accordingly, one of the principal objects of the present invention is to provide a method of accelerating the aforesaid vulcanization process.

Another object of this invention is to provide a method of accelerating those reactions of Butyl rubber with dimethylol phenols in which only a partial degree of cure is eifected to be followed by subsequent vulcanization with other vulcanizing agents.

Another object is to provide a method of accelerating the high-temperature reaction between Butyl rubber, dimethylol phenols and carbon black whereby, upon subsequent compounding and curing, vulcanizates are ob tained having abnormally high electrical resistively and low torsional hysteresis.

I have now discovered that the vulcanization of Butyl rubber with dimethylol phenols is greatly accelerated by the presence of a small amount of an organic sulfonic acid, and excellent cures can be obtained in a considerably shorter time, or at a lower temperature, than would otherwise be possible. A remarkable feature of the use of an organosulfonic acid to accelerate the dimethylol phenol cure of Butyl rubber is that, although the cure proceeds rapidly, there is no difiiculty from reversion and consequent loss'of physical properties if the curing conditions are unduly prolonged or severe. This resistance to reversion, characteristic of the vulcanizates of the invention, renders the present improved vulcanizates particularly well adapted for use in such articles as curing bags, that are exposed in service to temperatures that would ordinarily cause over-cure in conventional rubber stocks.

Butyl rubber, as is well known, is a commercial synthetic rubber made by copolymen'zing an isoolefin, usually isobutylene, with a minor proportion of a conjugated diolefin having from 4 to 14 carbon atoms per molecule. The isoolefins used generally have from 4 to 7 carbon atoms, and such isomonoolefins as isobutylene or ethyl methyl ethylene are preferred. The diolefin usually is one having from 4 to 6 carbon atoms, and is preferably isoprene or butadiene. The Butyl rubber contains only relatively small amounts of copolymerized diene, typically from about 0.5 to 5%, and seldom more than 10%, on the total weight of the elastomer. For the sake of convenience and brevity, the various possible synthetic rubbers within this class will be designated generally by the term Butyl rubbers.

In accordance with the invention, the Butyl rubber to be vulcanized is compounded with a dimethylol phenol, as curing agent, and an organosulfonic acid as the accelerator. The dimethylol phenol curing agents are known materials, and are typically made by reacting a 2,794,009 Patented May 28, 1957 para-substituted phenol having the two ortho positions unoccupied, with a considerable excess of formaldehyde, the molar ratio of formaldehyde to phenol typically being 2:1, in the presence of a strong alkaline catalyst, especially an alkali metal hydroxide. Typically the mixture of the phenol, formaldehyde and alkaline catalyst is heated at a suitable temperature, e. g., 25-100 0., whereby the formation of the methylol phenol, i. e., the para-substituted-2,6-dimethylol phenol, is eifected. This material, which is a phenol dialcohol, can be isolated by acidification of the mixture and separation of the oily layer, which can then be partially polymerized to the resol stage by heating it at elevated temperature, say 75- l75 C. This resol material has the advantage that it is more reactive with the Butyl rubber than is the lower molecular weight material. Isolation of the phenol dialcohol can be omitted, in which case the reaction is carried past the monomer stage to the resol stage, whereupon the mixture is neutralized and water is removed to give the resol. The resols are commercially available resins, sold under such trade names as Amberol ST-l37, and they are oil-soluble and heat-reactive; i. e., capable of being converted by heat to a cured state without any necessity for adding a formaldehyde-yielding curing agent, in contrast to the novolac type of phenolic resin, which is prepared in acid medium with a deficieny of formaldehyde and is permanently fusible and soluble unless a source of formaldehyde is added to advance the cure.

The phenol from which the dimethylol phenol is made generally has a hydrocarbon group in the position para to the phenolic hydroxyl, examples being alkyl groups especially alkyl groups having from 3 to 20 carbon atoms, of which tertiary-butyl and tt-octyl (alpha, alpha, gamma,

' gamma-tetramethyl-butyl) are especially preferred-cycloalkyl groups, aryl groups such as phenyl, and aralkyl groups such as benzyl and cumyl. Such inactive substituent in the para position serves to block this otherwise active position and prevent the formation of a trialcohol which would not serve the purposes of the invention.

Examples of suitable dimethylol phenols that can be used in the invention either in the polymeric or monomeric form are as follows:

2,6-dimethylol-4-methylphenol 2,6-dimethylol-4-t-butylphenol 2,6-dimethylol-4-tt-octylphenol 2,6-dimethylol-4-dodecylphenol 2,6-dimethylol-4-phenylphenol 2,6-dimethylol-4-benzylphenol 2,6-dimethylol-4-(alpha, alpha-dimethylbenzyl) phenol 2,6-dimethylol-4-cyclohexylphenol Any of the foregoing materials may be used either in the monomeric form, or in the polymeric, resol form. Mixtures of the resinous polymeric dimethylol phenols with more or less of low molecular weight or monomeric dimethylol phenols are also useful. The resinous dimethylol phenols are the preferred materials for use in the invention because they are more eifective, and more convenient to use. For the sake of convenience and brevity, the term dimethylol phenol, or 2,6-dimethylol- 4-hydrocarbon substituted phenol, will be used to refer to any of the monomeric or polymeric compounds, or to mixtures thereof, unless otherwise stated. 3 The resol or polymeric so-called 2,6-dimethylol-4-hydrocarbon substituted phenol is of course actually a limited self-condensation polymer of the monomeric 2,6- dimethylol-4-hydrocarbon substituted phenol. Such polymer is believed to be composed largely of molecules having at each end a phenolic nucleus providing a methylol group in each terminal ortho position; and in this sense the polymer 3 -59 itself is also a 2,6- dimethylol material. These terminal methylol groups render the resol polymer heat-reactive, in contrast to the novolac type of resin.

The dimethylol phenol is generally employed in amount within the range of from about 2 to 15 parts by weight to 100 parts of Butyl rubber. While smaller amounts of the dimethylol phenol may be employed, e. g., 1 part, it is usually found that less than this .tenths of a part of the organosulfonic acid in 100 parts of Butyl rubber, although I generally use somewhat more than this,say l to 5 parts per 100 parts of the Butyl rubber. Although even larger amounts of the accelerator can be used, say or parts, it is not generally necessary or desirable to use appreciably more than about 5 parts.

In carrying out the invention, the Butyl rubber, dimethylol phenol, and organosulfonic acid, and any additional desired ingredients, may be mixed together according to the procedures ordinarily used in mixing rubber compounds, with the aid of the usual rubber mixing equipment, such as an internal mixer or roll mills. The vulcanizable mixture resulting from the foregoing ingredients may be fabricated into the desired form by the usual methods, such as calendering, extrusion, or

molding, and subsequently vulcanized by heating, preferably while confined under pressure.

For the purpose of making such articles as curing bags or inner tubes, there is generally included in the mixture a quantity of a suitable reinforcing material, preferably carbon black. Although at least about to 100 parts by weight of carbon black may be employed per 100 parts of the Butyl rubber, it is generally preferred to use about 40 to 80 parts of black, most preferably about 50 or 60 parts. Other compounding ingredients, such as fillers, processing aids, etc., may be included in the mixture if desired.

The curing process of the invention is conveniently carried out at temperatures of 200 F. or higher, and preferably at temperatures in excess of 300 'F., for periods of time ranging from about 5 minutes to 3 hours, the lower the temperature the longer the curing time, and vice versa, within the stated ranges. Elastic products having the properties of typical vulcanized rubbery materials are obtained. temperatures are within the range of about 320 to 370 F., although somewhat higher temperatures may be employed, e. g., 390 or 400 F., provided that such highly elevated temperatures are not maintained for a sufiiciently long time to cause thermal injury to the article.

The following examples will serve to illustrate the invention in more detail. In the examples, the amounts of the various ingredients are all expressed in parts by weight.

EXAMPLE I Two stocks were made up by mixing the materials shown in the table below in the stated amounts, one of the stocks containing an organosulfonic acid, viz., p-toluenesulfonic acid, and the other stock containing no organosulfonic acid. Portions of the stocks were cured for the times and temperatures indicated in the table, and the properties of the resulting vulcanizates were then measured, with the results noted in the table. The

The most preferred vulcanizing Table I I-A I-B GET-25 100 Carbon black. 7O 70 Stearic acid 2 2 Light mineral oiL. 8 8 Amberol ST-l37 8 8 p-Toluencsnlfonic acid 2 .l Temperature of cure F" 315 330 Time of cure,

minutes 30 1, 100 550 Scott Tensile. 60 1,190 1, 020 1, 230 1, 230 30 430 820 Elongation at break 60 410 590 120 400 480 30 500 200 Modulus at 300%, Elongation 00 650 440 120 (590 700 It will be noted that the addition of a small amount of p-toluenesulfonic acid in stock I-A not only accelerated the rate of the cure but also allowed the cure to be made at a lower temperature: by the use of p-toluenesulfonic acid as accelerator, a good technical cure was obtained in 30 minutes at 315 F., whereas the unaccelerated stock IB required 60-120 minutes at 330 F. to realize the same degree of cure. The vulcanizate made from the accelerated stock exhibited unusual resistance to thermal reversion as well as resistance to cold flow. This was demonstrated by the fact that on continued cure the vulcanizate containing the accelerator did not revert, as do over-cured sulfur vulcanizates. This allows considerable tolerance in curing conditions and also illustrates the remarkable aging characteristics of the improved vulcanizates.

EXAMPLE II Table II represents the results obtained by carrying out an experiment similar to Example Land'using both aliphatic and aromatic sulfonic acids as accelerators.

Table II II-A IIB II-C II-D GET-15 100 100 100 100 Carbon b1a0k 70 7O 7O 70 Amberol ST-137 6 6 6 6 p-Toluenesulfonic acid- 2 BetarNapthalene-sulfonic acid. 2 Mixed alkanesultonie acids 2 Time of cure at 330 F., A B C .1) minutes 15 940 640 l, 170 30 420 990 '690 1, 220 Scott Tensile 60 740 1, 030 720 1, 240 120 920 1, 100 750 1, 180 240 1, 120 1,030 780 1, 170 15 L690 450 500 310 I 30 590 420 490 320 Elongation at break .60 510 410 480 310 120 460 420 470 300 240 400 390 420. 290 15 110 550 320 880 Modulus at 300% elonga- .30 260 570 350 900 tion 6O 480 570 370 900 120 690 630 V 400 980 240 850 670 400 1 Mixedalkanes ulfonic acids a mlxtnre containing equal parts 01 methane-, ethane-, and propanesultonie acids.

'5 It will be noted from Table II that when the mixed alkanesulfonicacids were .used for acceleration, the 151 minute curewas equivalent to a 4-hour unaccelerated cure. Again, it should be observed that prolonged overcure does not cause rapid reversion, as it does with sulfurcured systems. EXAMPLE III In this example the use of organosulfonic acids-to speed up the curing reaction of Butyl rubber with monomeric or polymeric dimethylol phenols is illustrated. In general,

any acceleration of the cure.

Table IV IVA IV-B rv-o rv-D IV-E -rv-F' rv-G Iv-In GRI- 100 100 100 100 100 100 100. 100 70 70 70. 7o 70 '70 70 70 s s s s ..s s '8 s s s -8 '8 s s s 3 Mixed alkanesulfonlc acids- 1 Beuzoic acid Acetic acid- Trlchloroacetic Phosphoric acid Sulfuric acid Hydrochloric ac Time of cure at 330F., minutes as 1 as 228 21s 0 00 Tensile 00 950 11320 940 1,000 700 880 030 1,040 240 1, 380 1,330 1,340 1,350 1,110 1,140 070 1,350 is 700 428 L250 258 5230 720 rim Elongamn break 00 000 400 020 590 500 000 550 500 v 240 430 300 410 430 420 500 540 430 5 $93 Sig 133 033"" 533 353 3 5 Mmiulus at 300% elmgatmm" 400 030 430 500 390 470 300 500 240 950 1,070 920 930 800 070 380 950 monomeric dimethylol phenols cure Butyl rubber at a rather slow rate. However, with acceleration, the cure The accelerating etfect of the organosulfonic acids on the reaction of dimethylol phenols with Butylrubber with monomeric dimethylol phenols assumes practical 45 can be taken advantage of alsoin processes where it is importance. desired to effect only a limited or partial cure of the Butyl Table III III-A III-B III-C III-D III-E III-F GRI-15 100 100 100 100 100 7o 70 70 6 Mixed alkanesulto 2 2 2 Time of cure at 330 F minutes 15 750 320 920 1, 170 30 150 840 670 1, 010 420 1, 220 Scott Tensile 60 360 870 1, 070 1, 090 740 1, 240 r 120 630 9180 1,31 Q.1, ,.e. 920 1, 030 1, 410 1, 120 1, 170 15 460 0 0 690 310 400 390 510 370 590 v 320 Elongation at break 60 480 330 430 360 510 31D 120 420 350 360 350 A60 300 240 390 310 280 340 3100 I 290 15 22 a; 3% a: 5 7 m i 300% 25o, 660 7 8,30 "8,50 480' 000 r 120 470 930 rubber by the dimethylol phenol. In such cases, the dered limited o p rti eac on ca be. ar i t in a .0 time, or at lower temperatures, by using the organosul-fonic acid as an accelerator in accordance with the invention. Thus, for example, the partial curing reaction between Butyl rubber and limited amounts of dimethylol phenol, for example, 0.2 to 2.5 parts per 100 parts of Butyl rubber, carried out at temperatures of 200 -400 F. for an inversely related period of time from 5-45 minutes, can be efiectively accelerated by the presence of a small amount (say (LS-2% on the weight of the rubber) of organosulfonic acid as described. Butyl rubber partially cured with dimethylol phenol and the process of making the same are disclosed in more detail and claimed in copending application Serial No. 290,344, filed May2 7, 1952, now Patent No. 2,702,287. Limited reaction of the Butyl rubber with the dimethylol phenol greatly increases the tolerance of the rubber for mineral oil, and as much as 50 parts of oil, per 100 parts of Butyl rubber, can be incorporated into the thus-modified Butyl rubber while still retaining good processing qualities. The mixture of Butyl rubber and oil can be compounded for vulcanization with any curatives suitable for Butyl rubber, and vulcanized under the usual conditions to provide a vulcanizate of good physical properties. If carbon black is present during the limited reaction between the Bu'tyl rubber and the dimethylol phenol, particularly at a temperature of 275400 F. for an inversely related time of about 5 to 30 minutes, and vulcanizing ingredients are thereafter incorporated and the mixture is vulcanized, it is found that the hysteresis of the vulcanizate is significantly lower than it would be if such pre-treatment were omitted. In any case, whether the improvement desired by the limited modification is increased oil tolerance or lower hysteresis, the accelerating method of the invention greatly facilitates attainment of the desired result by enhancing the Butyl rubber-dimethylol phenol reaction.

EXAMPLE V This example illustrates the modification of Butyl rubber to increase its compatibility with oil, by reacting it with relatively small amounts of a dimethylol phenol, first without employing any accelerator (Table V-a), then with a sulfonic acid added as accelerator according to my invention (Table V-b).

The degree of chemical modification of the elastomer is indicated by the changes in Mooney viscosity, percent of gel, and swelling index of the gel.

1 Reaction carried out in a size B Banbury (2 pounds capacity) rotor speed 50 R. P. M.

1 Modified Butyl converted to a crumb.

The data of Table V-b, when compared to those of Table V-a, clearly show the definite accelerating action of the organosulfonic acid. Without acceleration, the maximum changes observed were associated with .a reaction time of 20 minutes, after which the Butyl rubber begins to break down. With acceleration, the reaction occurs almost instantaneously, or after mixing only 5 minutes at 350 F., and the properties of the product remain remarkably constant over a wide range of heating time: i. e., there is a very marked plateau efiect. The degree of modification of the rubber in my process is far greater than the maximum observed with the unaccelerated compound. Stocks modified in this manner are well adapted for admixture therewith of considerable quantities of oils, as much as 50 parts of mineral oil per of Butyl rubber being readily assimilated.

EXAMPLE VI When the modification reaction, as described in Example V-b, is carried out in the presence of carbon black, the carbon black enters into the reaction, in some manner not fully understood, and one obtains stocks of un' usually low torsional hysteresis and high electrical resistivity. This reaction is greatly accelerated by the addition of as little as 1% of an organosulfonic acid (on the weight of the Butyl rubber), as shown by the data below (Table VI). Table VI illustrates the effect of carbon black, and the greater degree of reaction obtained with the accelerator of the invention present. The chemicals shown in Table VI, Part 1 were blended on a roll mill with the GR-I, and with the black when called for, and then milled in a Banbury for about 20 minutes at 350 F. (50 R. P. M.). Thereafter, the vulcanizing and other compounding ingredients shown in Part 2, including the black when called for, were added on a roll mill, and each of the stocks was then milled in a Banbury for 5 minutes at 225 F. (20 R. P. M.).

Table'Vl---Continued 4 FARM I 50 50 50 2, 180 2, 070 2, 410 2, 430 2, 080 Scott Tensile 60 2, 110 2,020 2, 390 2, 380 2, 210 75 2,150 2,440 2, 450 2, 290 45 540 470 580 0 o Elongation at break 510 420 540 440 630 4 420 530 440 620 45 1, 000 1, 080 880 1, 200 550 Modulus at 300% Elongation 60 1, 000 1, 240 9 1, 330 650 75 1, 080 1, 280 1, 050 1, 380 680 45 6.9 6.6 8.6 1a0 5 0 Log Elec. Resist 60 6.8 6.6 8.1 13. 0 4 9 75 6.8 6.5 8.1 5 0 45 .21 .24 .16 .08 34 Tort. Hyst. 280 F 60 21 .23 .16 08 34 76 21 .23 .16 0s 34 EXAMPLE VII 30 a control Butyl tread stock. The ingredients indicated b This exarrirfsle 11lust(riates the lfact that thehaccleleratlor under Part 1 were compounded on a n and then f y organosu omc an s not on y Increases t e egree 0 ther mixed in a'Banbury for 10 minutes at 325 F. The

reaction, but also allows the reaction to proceed at a lower temperature and at an increasedratg ingredients indicated under Part 2 were then added on a Table VII No Acceleration Acceleration A B C D E A B O D E 100 100 100 100 100 50 50 50 50 2 2 2 2 2 1 1 1 1 1 Time of Reaction. 10 5 20 60 Temperature of React 350 850 300 300 300 300 300 PHYSICAL PROPERTIES AFTER ADDITION OF SULFUR AND ACCELERATORS, AND 60 CURE AT 298 F.

A B C D E A B C D E Scott Tensile Elongation at break 630 540 520 490 490 Modulus at 300% Elong 1, 270 1, 270 1, 310 1, 1, 250 1, 300 1, 450 1, 420 1, 320 Tors. Hyst. at 280 F". .12 .10 .10 10 11 .082 .076 .068 072 Log. of elec. resist 7. 3 9. 2 10.0 11. 0 12.0 10.7 13 13 4 13 13 It will be evident from inspection of the data of Table 65 mill, following which the stocks were cured for 60 minutes VII that, without acceleration, the maximum reaction (as at 298 F. measured by modulus, torsional hysteresis and electrical Table VIII resistivity) is obtained in 30 minutes at 350 F. HoW- PART 1 ever, with acceleration according to my invention, a 5 I greater degree of reaction is realized in one third of the 70 time, at a temperature fifty degrees lower, viz., in 10 I minutes at 300 F.

. MPO Black--. EXAMPLE VIII Amberol ST137 p-Toluenesulfonic acid I In Table VIII are compared a low-hysteresis stock with .75 1 a EXAMPLE IX In the previously described low-hysteresis stocks the final cures were effected by using sulfur plus accelerators. This, however, is not necessary. Good cures may be obtained by using a dimethylol phenol as the final curing agent, with an organosulfonic acid as accelerator. In Table IX data are given for a low-hysteresis Butyl stock processed minutes at 300 F. with two part of Amberol ST-l37 and 1 part of mixed aliphatic sulfonic acids. The stock was cured minutes at 307 F. (60 lbs. steam). This compares favorably with a standard sulfur cure of 60 minutes at 298 F. (50 lbs. steam).

Table IX A B G (Control) GRI-15 100 100 100 IVIPC Black 50 50 Amberol ST-l37 2 2 4D p-Toluensulfonic a 1 Mixed Alkanesullonie acids. '1 Banbury Temperature .F 300 325 325 Time of reaction ..minutes.. 15 10 10 StookA.. 153 Stock B.-. 153

Stock 0 Amberol sT 1a7 Scott Tensile 14 2, ,100 Elongation at break. 440 400 430 Modulus at 300% Elong. 1, 150 1, 650 1, 325 'Iors. Hysteresis at 280 F .099 .0577 .271 Log of Elect. Resist 12. 31 12. 5 0. 0

The data show the attainment of low hystersis by the process of the invention, in a stock which, without my treatment, has a very high hysteresis.

The improved vulcanizates of the invention can be used to great advantage in making a variety of useful articles, suchas curing bags of the various known kinds, either for new tires or for re-treading tires, as well as in making hose, belts, inner tubes, especially heavy service inner tubes, and pneumatic tires, especially tire treads and side walls, as well as other objects.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. A method of modifying a rubbery copolymer of an isomonoolefin having from 4 to 7 carbon atoms with from 0.5 to 10% of a conjugated diolefin having from 4 to 14 carbon atoms comprising heating parts of the said rubbery copolymer in admixture with from 0.2 to 20 parts of a 2,6-dimethylol-4hydrocarbon substituted "5 12 phenol and from 0.3 to 15 parts of an organosulfonic acid selected from the group consisting of aliphatic and aromatic sulfonic acids, at a temperature of ZOO-400 F., for a period of time of from 5 minutes to 3 hours inversely related to the temperature.

2.. A method of modifying a rubbery copolymer of an isomonoolefin having from 4 to 7 carbon atoms with from 0.5 to 10% of a conjugated diolefin having from 4 to 14 carbon atoms comprising heating 100 parts of the said rubbery copolymer in admixture with from 0.2 to 20 parts of a 2,6 dimethylol-4-hydrocarbon substituted phenol resol and from 0.3 to 15 parts of an organosulfonic acid selected from the group consisting of aliphatic and aromatic sulfonic acids, at a temperature of 200400 F., for a period of time of from 5 minutes to 3 hours inversely related to the temperature.

3. A method of modifying a rubbery copolymer of an isomonoolefin having from 4 to 7 carbon atoms with from 0.5 to 10% of a conjugated diolefin having from 4 to 14 carbon atoms comprising heating 100 parts of the said rubbery copolymer in admixture with from 0.2 to 20 parts of a 2,6-dimethylol-4-hydrocarbon substituted phenol resol and from 0.3 to 15 parts of an aliphatic sulfonic acid, at a temperature of 200-400 P., for a period of time of from 5 minutes to 3 hours inversely related to the temperature.

4. A method of modifying a rubbery copolymer of an isomonoolefin having from 4 to 7 carbon atoms with from 0.5 to 10% of a conjugated diolefin having from 4 to 14 carbon atoms comprising heating 100 parts of the said rubbery copolymer in admixture with from 0.2 to 20 parts of a 2,6-dimethylol-4-hydrocarbon substituted phenol resol and from 0.3 to 15 parts of an aromatic sulfonic acid, at a temperature of 200-400" F., for a period of time of from 5 minutes to 3 hours inversely related to the temperature.

5. A method of modifying a rubbery copolymer of an isomonoolefin having from 4 to 7 carbon atoms with fromv 0.5 to 10% of a conjugated diolefin having from 4 to 14 carbon atoms comprising heating 100 parts of the said rubbery copolymer in admixture with from 0.2 to 20 parts of a 2,6-dimethylol-4-hydrocarbon substituted phenol resol and from 0.3 to 15 parts of an alkane sulfonic acid, at a temperature of ZOO-400 R, for a period of time of from 5 minutes to 3 hours inversely related to the temperature.

6. A method of modifying a rubbery copolymer of an isomonoolefin having from 4 to 7 carbon atoms with from 0.5 to 10% of a conjugated diolefin having from 4 to 14 carbon atoms comprising heating 100 parts of the said rubber copolymer in admixture with from 0.2 to 20 parts of a 2,6-dimethylol-4-hydrocarbon substituted phenol resol and from 0.3 to 15 parts of p-toluenesulfonic acid, at a temperature of ZOO-400 F., for a period of time of from 5 minutes to 3 hours inversely related to the temperature.

7. A method of modifying a rubbery copolymer of an isomonoolefin having from 4 to 7 carbon atoms with from 0.5 to 10% of a conjugated diolefin having from 4 to 14 carbon atoms comprising heating 100 parts of the said rubbery copolymer in admixture with from 0.2 to 20 parts of a 2,6-dimethylol-4-hydrocarbon substituted phenol resol and from 0.3 to 15 parts of beta-naphthalenesulfonie acid, at a temperature of 200400 F., for a period of time of from 5 minutes to 3 hours inversely related to the temperature.

8. A method of vulcanizing a rubbery copolymer of a conjugated diolefin having from 4 to 6 carbon atoms with an isomonoolefin having from 4 to 7 carbon atoms, said copolymer containing from 0.5 to 10% of said diolefin, comprising heating the said copolymer with from 2 to 20% of a 2,6-dimethylol-4-alkyl phenol resol and from 0.3 to 15 parts of an organosulfonic acid selected from the group consisting of aromatic and aliphatic sulfonic acids at a temperature of ZOO-400 F for a period 13 of time of from minutes to 3 hours inversely related to the temperature.

9. A method of vulcanizing a rubbery copolymer of isoprene and isobutylene containing from 0.5 to 5% of isoprene, comprising heating the said copolymer with from 2 to 20% of a 2,6-dimethylol-4-alkyl phenol resol and from 0.3 to 15 parts of p-toluenesulfonic acid, at a temperature of 200-400 F., for a period of time of from 5 minutes to 3 hours inversely related to the temperature.

10. The method of modifying a rubbery copolymer of an isomonoolefin having from 4 to 7 carbon atoms with from 0.5 to 10% of a conjugated diolefin having from 4 to 14 atoms which comprises heating the said rubbery copolymer with from 0.2 to 2.5% of a 2,6-dimethylol-4- hydrocarbon substituted phenol and with a small amount, efiective to accelerate the reaction of the said rubbery copolymer and the phenolic material, of an organosulfonic acid selected from the group consisting of aliphatic and aromatic sulfonic acids at a temperature of 200-400" F. for an inversely related period of from 5 to 45 minutes, and thereafter incorporating in the reaction product up to 50 parts of mineral oil per 100 parts of the said rubbery copolymer, and vulcanizing ingredients, and vulcanizing the mixture.

11. The method of producing a rubbery copolymer of an isomonoolefin having from 4 to 7 carbon atoms with from 0.5 to 10% of a conjugated diolefin having from 4 to 14 carbon atoms and carbon black vulcanizates of low torsional hysteresis which comprises heating the said rubbery copolymer containing a relatively large amount of rubber-reinforcing carbon black with from 0.2 to 2.5%, on the weight of rubber, of 2,6-dimethy1ol-4-hydrocarhon-phenol, and with a small amount, effective to accelerate the reaction of the rubber with the phenolic material and the carbon black, of an organosulfonic acid selected from the group consisting of aliphatic and aromatic sulfonic acids, at a temperature of 275-400" F. for an inversely related time of about 5 to minutes, and thereafter incorporating in the product vulcanizing ingredients, and vulcanizing the mixture.

References Cited in the file of this patent UNITED STATES PATENTS 2,649,431 Little -n Aug. 18, 1953 FOREIGN PATENTS 492,906 Great Britain Sept. 29, 1938 OTHER REFERENCES Serial No. 357,662, Wildschut (A. P. 0.), published April 20, 1943. 

1. A METHOD OF MODIFYING A RUBBERY COPOLYMER OF AN ISOMONOOLEFIN HAVING FROM 4 TO 7 CARBON ATOMS WITH FROM 0.5 TO 10% OF A COMJUGATED DIOLEFIN HAVING FROM 4 TO 14 CARBON ATOMS COMPRISING HEATING 100 PARTS OF THE SAID RUBBERY COPOLYMER IN ADMISTURE WITH FROM 0.2 TO 20 PARTS OF A 2,6-DIMETHYLOL-4-HYDROCARBON SUBSTITUTED PHENOL AND FROM 0.3 TO 15 PARTS OF AN ORGANOSULFONIC ACID SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC AND AROMATIC SULFONIC ACIDS, AT A TEMPERATURE OF 200-400*F., FOR A PERIOD OF TIME OF FROM 5 MINUTES TO 3 HOURS INVERSELY RELATED TO THE TEMPERATURE. 